KR102598343B1 - Conductive Particles, Conductive materials used the same - Google Patents

Abstract

The present invention relates to a conductive particle including a core and a conductive layer provided on the surface of the core and having protrusions, a first palladium region formed at the interface between the conductive layer and the core, and an inner region of the protrusions. It is characterized in that it contains palladium distributed in the third palladium region.

Description

Conductive particles, conductive materials and connection structures {Conductive Particles, Conductive materials used the same}

The present invention relates to conductive particles having a conductive layer on the surface of the core, and more specifically, to conductive particles used as a core conductive material for an anisotropic conductive adhesive material connecting fine pitch circuits. It also relates to conductive materials and connection structures using the above-described conductive particles.

Conductive particles are anisotropic conductive materials used in dispersed form by mixing with a hardener, adhesive, and resin binder, such as anisotropic conductive film, anisotropic conductive adhesive, and anisotropic conductive paste. It is used for anisotropic conductive ink, anisotropic conductive sheet, etc.

The anisotropic conductive material includes FOG (Film on Glass; flexible substrate - glass substrate), COF (Chip on Film; semiconductor chip - flexible substrate), COG (Chip on Glass; semiconductor chip - glass substrate), FOB (Film on Board; It is used for flexible substrates (glass epoxy substrates), etc.

Assuming that the anisotropic conductive material is used to bond a semiconductor chip and a flexible substrate, for example, the anisotropic conductive material is placed on the flexible substrate, the semiconductor chips are stacked, and the anisotropic conductive material is cured under pressure/heating so that the conductive particles form the electrodes of the substrate. A connection structure that electrically connects the electrodes of a semiconductor chip can be implemented.

When used in the anisotropic conductive material, the conductive particles are mixed with a hardener, adhesive, resin binder, etc., and when used as a connection structure after pressurization/heating, the electrical connection between the upper and lower electrodes is maintained by curing/adhesion of the anisotropic conductive material. do.

Korea Publication No. 10-2017-0072169 (2017.06.26.)

The present invention was developed to solve the above-mentioned problems, and the technical problem to be achieved by the present invention is to provide conductive particles that allow the conductive layer to be formed with a stable and uniform thickness and to control the size of the protrusions formed in the conductive layer. The purpose is to

The conductive particle according to one aspect of the present invention is,

A conductive particle comprising a core and a conductive layer provided on the surface of the core and having protrusions,

It is characterized in that it includes palladium distributed in a first palladium region formed at the interface between the conductive layer and the core, and a third palladium region formed in the inner region of the protrusion.

At this time, it is preferable to include a second palladium region formed in the middle of the conductive layer.

In addition, the third palladium region preferably includes palladium nanoclusters with an average particle diameter of 30 nm to 130 nm.

In addition, the first palladium region has more palladium nanoparticles distributed than the surrounding area, and it is preferable that the palladium nanoparticles are attached to more than 95% of the core surface area.

In addition, the second palladium region is an area where palladium nanoparticles are distributed more than the surrounding area.

In addition, it is preferable that the palladium concentration in the third palladium region is higher than the palladium concentration in the first palladium region or the second palladium region.

Additionally, the conductive layer is preferably made of one or more alloys selected from the group consisting of Ni, Sn, Ag, Cu, Pd, Zn, W, P, B, and Au.

In addition, it is preferable to further include an insulating layer or insulating particles on the surface of the conductive layer.

In addition, it is preferable that the outermost layer of the conductive layer is treated for rust prevention using a hydrophobic rust preventive agent.

Another aspect of the present invention is an anisotropic conductive material containing the above-described conductive particles.

Another aspect of the present invention is a connection structure containing the above-described conductive particles.

Another aspect of the present invention includes manufacturing a core;

Forming a first palladium region by attaching palladium particles to the surface of the core;

forming a first nickel region by dispersing the core after step B) in a nickel plating solution;

Forming a second palladium region by adding a reducing agent to the core after step C) and then injecting a palladium precursor solution;

Forming a second nickel region by injecting a nickel precursor into the second palladium region after step D);

Forming a third palladium region including palladium nanoclusters in one area of the surface of the second nickel region by adding a palladium precursor solution and a stabilizer to the core; and

It provides a method of manufacturing conductive particles including forming a third nickel region on the second nickel region and the third palladium region.

In the conductive particle according to the present invention, palladium is provided at the interface of the conductive layer with the core, allowing the elements forming the conductive layer to grow.

In addition, palladium is included within the conductive layer, which has the effect of forming the conductive layer with a stable and uniform thickness.

In addition, palladium is contained in the form of nanoclusters inside the protrusions protruding from the conductive layer and performs a protrusion formation function, and has the effect of controlling the size and height of the protrusions depending on the size of the palladium nanoclusters.

As a result, the conductive layer has a uniform thickness on the core, and the size and height of the protrusions can be adjusted to suit the conditions of use, easily piercing the oxide film of the electrode and providing highly stable conductive particles, anisotropic conductive materials, and connection structures. can be manufactured.

Figure 1 is a TEM photograph of a conductive particle according to an embodiment of the present invention.
Figure 2 is a TEM photograph of a conductive layer region without protrusions of conductive particles according to an embodiment of the present invention.
Figure 3 is a graph showing the results of EDAX analysis in the middle region where there are no protrusions of the conductive layer.
Figure 4 is a TEM photograph of the protruding area of the conductive layer of conductive particles according to an embodiment of the present invention.
Figure 5 is a graph of EDAX analysis results in the middle region of the protrusion.

Before describing the present invention in detail below, it is understood that the terms used in this specification are only for describing specific embodiments and are not intended to limit the scope of the present invention, which is limited only by the scope of the appended claims. shall. All technical and scientific terms used in this specification have the same meaning as generally understood by those skilled in the art, unless otherwise specified.

Throughout this specification and claims, unless otherwise stated, the terms comprise, comprises, and comprise mean to include the mentioned article, step, or group of articles, and steps, and any other article. , it is not used in the sense of excluding a step, a group of objects, or a group of steps.

Meanwhile, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as being particularly preferred or advantageous may be combined with any other feature or feature indicated as being preferred or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the attached drawings.

<Challenger>

Conductive particles according to an embodiment of the present invention are conductive particles included between electrodes to electrically connect the electrodes, and at least one of the electrodes is provided with an oxide film on the surface.

Generally, conductive particles are included in an anisotropic conductive material and heated and compressed. When compressed, the size of the conductive particles changes and protrusions penetrate the electrodes, thereby electrically connecting the electrodes. At this time, the gap between electrodes varies depending on the size of the particles used, but is usually about 3㎛ to 20㎛.

The conductive particles include a core and a conductive layer provided with protrusions provided on the surface of the core.

The core according to this embodiment is not particularly limited. For example, the core may use resin particles or organic-inorganic hybrid particles.

The resin particles can be prepared using seed polymerization, dispersion polymerization, etc. using urethane-based, styrene-based, acrylate-based, benzene-based, epoxy-based, amine-based, imide-based monomers, modified monomers thereof, or mixed monomers of the above monomers. It is a copolymer obtained by polymerization using methods such as suspension polymerization and emulsion polymerization.

The organic-inorganic hybrid particles are particles containing both organic and inorganic substances, and may have a core-shell structure, a compound structure, or a composite structure. At this time, when it has a core-shell structure, when the core is an organic material, the shell is an inorganic material, and when the core is an inorganic material, the shell is an organic material. The organic used here is the monomer, modified monomer, or mixed monomer, and the inorganic used is SiO ₂ , TiO ₂ , Al ₂ O ₃ , oxides including ZrO 2 , AlN, _{Si 3 N 4} , TiN, and BaN. Nitride, including WC, TiC, and carbide, including SiC, can be used.

Methods for forming the shell include chemical coating, sol-gel method, spray coating, CVD (chemical vapor deposition), PVD (physical vapor deposition), and plating methods.

In addition, a form in which inorganic particles are dispersed in an organic matrix having a compound structure is possible, a form in which organic particles are dispersed in an inorganic matrix, and a form in which organic/inorganic particles are dispersed in a 50:50 ratio are also possible.

Additionally, in the case of a compound structure, materials containing polysiloxane or metaloxane may be used.

The size of the core is not particularly limited, but considering the general electrode shape and surface roughness, it is preferably 6 ㎛ or less, more preferably 1.5 ㎛ to 5 ㎛, and even more preferably 1.5 to 4.5 ㎛.

The conductive layer may be composed of one or more elements such as P, B, Cu, Au, Ag, W, Mo, Pd, Co, and Pt on a Ni base. At this time, the conductive layer forms one layer, but inside it consists of a single layer with changes in concentration of each element except Ni.

According to embodiments of the present invention, among the elements forming the conductive layer, Pd is formed in the first palladium region formed at the interface of the conductive layer with the core, the second palladium region formed inside the middle of the conductive layer, and the inside of the protrusion. It is distributed in the third palladium area. At this time, this does not mean that palladium is not distributed at all except for the first palladium region, the second palladium region, and the third palladium region, but it does mean that the defined palladium region exists at a relatively high concentration compared to other surrounding regions. .

Figure 1 is a TEM photograph of a conductive particle according to an embodiment of the present invention. According to this, the conductive particles show a first palladium region (10), a second palladium region (20), and a third palladium region (30) according to the region in which palladium is distributed.

The first palladium region 10 is formed by including palladium nanoparticles at the interface with the core within the conductive layer, which allows the remaining particles to form the conductive layer to grow well on the palladium nanoparticles. At this time, the palladium nanoparticles are adhered to more than 95% of the surface of the core, preferably more than 99%, and more preferably to the entire surface.

The second palladium region 20 is formed by including palladium nanoparticles in the middle region of the conductive layer, and the particles that will form the conductive layer, mainly Ni particles, are distributed once again in the middle region of the conductive layer. By doing this, the remaining particles that make up the conductive layer are stacked thickly, allowing the overall conductive layer to become thicker.

The third palladium region 30 is an area in which palladium is distributed inside the protrusion area, and palladium is distributed in the widest area. The third palladium region contains palladium nanoclusters, and the palladium clusters are distributed inside the conductive layer and perform the function of forming the core of the protrusion, and the particles that will form the conductive layer on top, that is, Ni, combine to form protrusions on the conductive layer. form At this time, the palladium nanocluster preferably has a particle size of 30 nm to 130 nm. If it is less than the above range, it is too small to perform the protrusion forming function, and if it exceeds the range, there is a problem in that the protrusions become excessively large or the protrusions cannot be formed uniformly.

As a result, the conductive layer is formed by growing Ni, Pd, P, B, Cu, Au, Ag, W, Mo, Co, and Pt particles, forming a polycrystal.

The appropriate thickness of the conductive layer of the conductive particles is about 30 to 300 nm. If the thickness of the conductive layer is thin, the resistance value increases, and if it is too thick, peeling of the conductive layer and core occurs even if the conductive particles are slightly deformed under the heating/pressure bonding conditions of the anisotropic conductive material, reducing product reliability. The preferred thickness is 80~200nm.

The surface layer of the conductive layer of the conductive particles may contain precious metals such as gold, silver, platinum, and palladium. This is because the conductivity of conductive particles can be increased and an oxidation prevention effect can be obtained. The method of forming the surface layer is not particularly limited, and conventionally known techniques such as general sputtering, plating, and deposition can be used.

The shape of the protrusions of the conductive particles is not particularly limited, and may be spherical, oval, or in the form of multiple particles gathered together to form a cluster. The most desirable protrusion shape is mountain-shaped.

The size of the protrusion is not particularly limited, and is preferably in a convex shape of 50 to 500 nm. If the size of the protrusion is too small or too large, the effect of breaking the metal oxide layer and the binder resin is weakened, so a more preferable protrusion size is 100 to 300 nm.

The method of manufacturing conductive particles according to embodiments of the present invention is not particularly limited. For example, a catalyst material can be applied to the surface of the core resin particles, and a conductive layer and protrusions can be formed through electroless plating. However, in order to create the necessary concentration gradient when forming a conductive layer, it is desirable to add elements in multiple stages while changing their concentrations.

It is preferable that the outermost layer of the conductive particle according to the embodiment of the present invention has an insulating layer. As electronic products become smaller and more integrated, the pitch of the electrodes becomes smaller, so if there are no insulating particles on the outermost layer, electrical conduction occurs with adjacent electrodes.

Methods for forming an insulating layer include a method of chemically attaching insulating particles to the outermost layer of a conductive particle using a functional group, and a method of dissolving an insulating solution in a solvent and coating it by spraying or immersion.

It is preferable that the conductive layer of the conductive particles of the present invention is subjected to anti-rust treatment. This is because rust prevention treatment increases the contact angle with water, increasing reliability in a high-humidity environment, and has the effect of reducing performance degradation of connection members due to impurities dissolving in water. Therefore, it is preferable to use a hydrophobic rust preventive including a phosphoric acid ester type or salt thereof containing phosphoric acid, an alkoxysilane type containing silane, an alkylthiol type containing thiol, or a dialkyl disulfide type containing sulfide. After dissolving the rust preventive agent in a solvent, methods such as immersion or spraying can be used.

The size of the conductive particles is not particularly limited, but is preferably 6 μm or less. More preferably, 5 μm or less is appropriate. This is because where the anisotropic conductive material manufactured using the conductive particles of the present invention is used, the electrode gap is very small and is rarely used at a thickness of 6 ㎛ or more.

<Method for producing conductive particles>

The method of manufacturing conductive particles according to an embodiment of the present invention may include a core dispersion step (S1), a protruding conductive layer forming step (S2), and a rust prevention step (S3), where the rust prevention step (S3) is optional. may be included.

At this time, the core dispersion step (S1) includes a core particle synthesis step (S1a) and a plating catalyst activation step (S1b).

First, in the core particle synthesis step (S1a), urethane-based, styrene-based, acrylate-based, benzene-based, epoxy-based, amine-based, imide-based monomers or modified monomers thereof or mixed monomers of the above monomers are used to form seeds. A copolymer is produced by polymerization, dispersion polymerization, suspension polymerization, emulsion polymerization, etc.

When the organic-inorganic hybrid particle has a core-shell structure, when the core is organic, the shell is inorganic, and when the core is inorganic, the shell is organic. The organic used here is the monomer, modified monomer, or mixed monomer, and the inorganic used is oxides including SiO2, TiO2, Al2O3, and ZrO2, nitrides including AlN, Si3N4, TiN, and BaN, and WC, TiC, and SiC. Including carbides, etc. can be used.

Methods for forming the shell include chemical coating, sol-gel, spray coating, CVD (chemical vapor deposition), PVD (physical vapor deposition), and plating methods.

In addition, a form in which inorganic particles are dispersed in an organic matrix is possible, a form in which organic particles are dispersed in an inorganic matrix, and a form in which organic/inorganic particles are dispersed in a 50:50 ratio are also possible.

For example, the organic material used is ethoxylate triacrylate monomer and ethoxylate diacrylate monomer to disperse a solution in which a solvent and a polymerization initiator are mixed. At this time, the dispersion treatment may include homogenizer treatment using ultrasonic waves.

Additionally, a solution containing a dispersion stabilizer and a surfactant is added to the dispersion treatment solution and subjected to a polymerization process under elevated temperature conditions to form core resin fine particles.

Next, in the plating catalyst activation step (S1b), the core particles prepared in step S1a are activated with an electroless plating catalyst.

Specifically, in the plating catalyst activation step (S1b), the core particles are treated with a surfactant and then pretreated using various known methods to sensitize the electroless plating catalyst, and then the sensitized core particles are converted into a precursor for the electroless metal plating catalyst. It is added to a solution containing it and an activation treatment is performed.

The activated core particles are placed in a solution containing a strong acid and stirred at room temperature to perform accelerated treatment to obtain catalyst-treated core particles for electroless plating. At this time, it is preferable to use palladium as a catalyst for electroless plating, and at this time, the catalyzed palladium forms the first palladium region.

Next, the protruding conductive layer forming step (S2) includes a core dispersion step (S2a) and a protruding conductive layer forming step (S2b).

In the core dispersion step (S2a), the core is dispersed by putting it in a nickel base alloy plating solution, and nickel particles are plated on the surface of the core with the nickel base alloy plating solution to form a first nickel region.

At this time, the nickel base alloy plating solution is prepared by sequentially dissolving the precursor of the nickel alloy element, complexing agent, lactic acid, stabilizer, and surfactant, and the catalyst-treated core particles obtained in step (S1b) are added to the prepared plating solution. and perform dispersion treatment using an ultrasonic homogenizer.

It is preferable to adjust the pH of the dispersion treatment solution to pH 5.5~6.5 using aqueous ammonia, etc., as this can improve the adhesion and dispersibility of the insulating particles and the conductive layer in the initial Ni reduction reaction in the conductive layer formation step (S2b) described later. do. If the pH is less than 5.5, for example, pH 4 or less, adhesion and dispersibility are good, but the reactivity is so low that some particles may not be plated, and if the pH is higher than 6.5, the surface of the conductive layer becomes rough due to abnormal precipitation of Ni. This may result in poor adhesion and dispersibility.

The step of forming a conductive layer with protrusions (S2b) is a step of forming a conductive layer with protrusions by injecting a nickel precursor solution and a palladium precursor solution.

After the core dispersion step (S2a), a reducing agent is added to the core on which the first nickel region is formed on the surface, and then a palladium precursor solution is injected to form a second palladium region. A nickel precursor is added to the second palladium region to further form a second nickel region to increase the thickness of the conductive layer.

Next, the palladium precursor solution and stabilizer are again added to the surface of the second nickel region to form a third palladium region in one region of the surface. At this time, the third palladium region is formed in a section on the second nickel region in which palladium nanoparticles form a cluster to form particles larger than individual nanoparticles.

As a result, the surface is divided into a second nickel region and a third palladium region, and when the nickel precursor solution is injected into each upper part, nickel is formed on the top of the second nickel region and the third palladium region, forming protrusions and forming a conductive layer. A thickening third nickel region is formed.

That is, the mechanism by which protrusions are formed in the above-described manufacturing method is assumed to be as follows. When a reducing agent in an aqueous plating solution and an aqueous Ni solution are added, nickel particles are simultaneously generated by the reducing agent, and the nickel particles are attached to the surface of the particles to form a first nickel region. To form a thicker plating layer, a low concentration of Pd precursor solution is added to adsorb Pd particles on the first nickel region, and at the same time, the reduced nickel nanoparticles form the second nickel region. Afterwards, to form protrusions, a high concentration of Pd precursor solution and stabilizer are added to form large Pd clusters, and palladium nanoclusters play a role as nuclei in protrusion formation. Afterwards, a Ni precursor solution and a reducing agent are added to cover the surface with nickel, forming a conductive layer with raised protrusions of the palladium nanoclusters.

Meanwhile, when forming a conductive layer, a solution containing a precursor of at least one element selected from the group consisting of P, B, Cu, Au, Ag, W, Mo, Pd, Co, and Pt is added separately to create a concentration gradient of each element. A conductive layer with protrusions can be formed.

For example, in the core dispersion step (S2a), one or more precursors selected from P and B are added, and in the conductive layer formation step (S2b), one type of precursor selected from Cu, Au, Ag, W, Mo, Pd, Co, and Pt is added. The alloy elements containing the precursors of the above-selected elements can be divided and added to form a protruding conductive layer with a concentration gradient.

At this time, the alloy elements that are divided can be divided and added 2 to 5 times at intervals of 10 to 30 minutes, and 2 to 4 times at 15 to 25 minutes intervals. At this time, the input amount is divided into increased amounts or added continuously if necessary, but it is preferable to increase the input amount according to the input speed over a certain period of time, as this can increase the concentration in the direction toward the protrusion.

The optional rust prevention step (S3) can be performed by adding conductive particles to the rust preventive solution, but is not limited to this.

As the rust preventive solution, a hydrophobic rust preventive agent can be used, including a phosphoric acid ester-based or salt-based solution containing phosphoric acid, an alkoxysilane-based containing silane, an alkylthiol-based containing thiol, and a dialkyl disulfide-based containing sulfide. As the hydrophobic rust preventive, electroless nickel rust preventive, including the product name SG-1 sold by MSC, can be used.

After adding the conductive particles, ultrasonic treatment, etc. may be performed.

<Anisotropic conductive materials>

An anisotropic conductive material can be produced by dispersing the conductive particles of the present invention in a binder resin. Examples of anisotropic conductive materials include anisotropic conductive paste, anisotropic conductive film, and anisotropic conductive sheet.

The resin binder is not particularly limited. Examples include vinyl-based resins such as styrene-based, acrylic-based, and vinyl acetate-based, thermoplastic resins such as polyolefin-based and polyamide-based, and curable resins such as urethane-based and epoxy-based. The above resins may be used alone or in combination of two or more types.

For the purpose of polymerizing or curing the resin, a radical initiator such as Benzoyl peroxide (BPO), a photoinitiator such as Timethylbenzoyl phenylphosphinate (TPO), or an epoxy latent curing agent such as HX3941HP can be used alone or in combination.

Additionally, other materials may be added to the anisotropic conductive material binder resin to the extent that they do not impair the achievement of the purpose of the present invention. For example, colorants, softeners, heat stabilizers, light stabilizers, antioxidants, inorganic particles, etc.

The manufacturing method of the anisotropic conductive material is not particularly limited. For example, conductive particles can be uniformly dispersed in a resin binder and used as an anisotropic conductive paste, and they can also be spread thinly on release paper and used as an anisotropic film.

<Connection structure>

The connection structure according to an embodiment of the present invention connects circuit boards between circuit boards using conductive particles according to an embodiment of the present invention or an anisotropic conductive material according to an embodiment of the present invention. For example, it can be used as a method of connecting the display semiconductor chip of a smartphone and the glass substrate that makes up the circuit, or connecting the flexible board that makes up the circuit, or connecting μ -LED, mini-LED, and the circuit board.

The connection structure of the present invention does not cause circuit malfunction due to poor circuit connection or sudden increase in resistance.

Hereinafter, the present invention will be described in more detail through specific and various examples. However, this is intended to aid understanding of the present invention and the technical idea of the present invention is not limited thereto.

[Example]

Example 1

1) Manufacturing core resin particles (S1a)

800g of monomers TMPETA (Trimethylolpropane ethoxylate triacrylate), 50g of HDEDA (1,6-hexanediol ethoxylate diacrylate), and 800g of DVB (Divinylbenzrne) were added to a 3L glass beaker, and 5g of initiator BPO was added and treated in a 40kHz ultrasonic bath for 10 minutes to prepare the first solution. .

A second solution was prepared by dissolving 500 g of dispersion stabilizer PVP (Polyvinylpyrrolidone)-30K and surfactant Solusol (Dioctyl sulfosuccinate sodium salt) in 4,000 g of deionized water in a 5L PP beaker.

The first solution and the second solution were placed in a 50L reactor, 41,000g of deionized water was added, treated with an ultrasonic homogenizer (20kHz, 600W) for 90 minutes, and the temperature was raised to 85°C while rotating the solution at 120rpm. After the solution reached 85°C, it was maintained for 16 hours and subjected to a polymerization process.

The polymerized fine particles were filtered, washed, classified, and dried to obtain core resin fine particles. The average diameter of the manufactured core resin fine particles was determined using the mode value measured using a Particle Size Analyzer (BECKMAN MULTISIZER TM3). At this time, the number of core particles measured was 75,000. The average diameter was 3.02㎛.

2) Catalyst treatment process (S1b)

30 g of the core resin particles prepared above were placed in a solution of 800 g of deionized water and 1 g of surfactant Triton . At the end of the cleaning and degreasing process, a water washing process was performed three times using 40°C deionized water.

Subsequently, Pd catalyst treatment was performed. After dissolving 150 g of stannous chloride and 300 g of 35-37% hydrochloric acid in 600 g of deionized water, the washed and degreased core resin particles were added, sensitized by immersion and stirring for 30 minutes at 30°C, and then washed with water three times. .

The sensitized core resin particles were added with 1 g of palladium chloride and 200 g of 35-37% hydrochloric acid into 600 g of deionized water, and activated at 40°C for 1 hour. After the activation treatment, a water washing process was performed three times.

The activated core resin particles were placed in a solution of 35-37%, 100 g of hydrochloric acid, and 600 g of deionized water and stirred at room temperature for 10 minutes for accelerated treatment. After the accelerated treatment, washing was performed three times to obtain catalyzed core resin particles for electroless plating.

3) Core distribution (S2a)

In a 5L reactor, dissolve 260g of nickel sulfate as a Ni salt, 5g of sodium acetate as a complexing agent, 2g of lactic acid as a complexing agent, 0.001g of Pb-acetate as a stabilizer, 0.001g of sodium thiosulfate, and 0.03g of Triton 80 as an anti-agglomeration agent in 3,200g of deionized water in a 5L reactor to prepare a plating solution. (a) was prepared. The catalyst-treated core resin particles were added to the prepared solution (a) and dispersed for 10 minutes using an ultrasonic homogenizer. After dispersion treatment, solution (b) was prepared by adjusting the solution pH to 5.5 using aqueous ammonia.

4) Formation of conductive layer with protrusions (S2b)

Solution (c) was prepared by dissolving 350 g of deionized water and 200 g of sodium hypophosphite, a reducing agent, in a 1L beaker.

Solution (d) was prepared by dissolving 250 g of deionized water, 100 g of nickel sulfate, and 10 g of hydrochloric acid in a 1L beaker.

Solution (e) was prepared by dissolving 100 g of deionized water, 0.005 g of PdCl2, and 10 g of hydrochloric acid in a 1L beaker.

Solution (f) was prepared by dissolving 400 g of deionized water and 300 g of sodium hypophosphite, a reducing agent, in a 1L beaker.

A solution (g) was prepared by dissolving 100 g of deionized water, 0.05 g of PdCl2, 30 g of hydrochloric acid, the stabilizer Triton X-100, and 10 g of sodium hypophosphite in a 1L beaker.

Solution (h) was prepared by dissolving 200 g of deionized water and 150 g of sodium hypophosphite, a reducing agent, in a 1L beaker.

Solution (i) was prepared by dissolving 150 g of deionized water, 50 g of nickel sulfate, and 10 g of hydrochloric acid in a 1L beaker.

While maintaining the temperature of the 5L reactor (solution (b-1)) at 55°C, solution (c) was introduced at a rate of 10 g per minute using a metering pump, and the reactor temperature was heated and maintained to reach 75°C in 35 minutes. did.

After the addition of the solution (c) is completed, it is maintained for 10 minutes, and after the addition of solution (e), it is maintained for 5 minutes, and solutions (d) and (f) are simultaneously introduced at the rate of 10 g per minute using a metering pump.

After the solutions (d) and (f) are completely added, they are maintained for 10 minutes and solution (g) is added and maintained to form clusters.

After the solution (g) is completely added, it is maintained for 10 minutes, and solution (h) and solution (i) are added at a rate of 10 g per minute using a metering pump.

After the solution (h) and solution (i) were added and maintained for 10 minutes, Ni plated protruding conductive particles were obtained.

Comparative Example 1

In Example 1, solution (c) was prepared with 200 g of deionized water and 150 g of sodium hypophosphite as a reducing agent, and plating was performed. After disintegration and fixation were performed to loosen the agglomeration of the conductive particles, 200 g of deionized water and 150 g of sodium hypophosphite as a reducing agent were added. Solution (d) containing 150 g of sodium, 10 g of Triton

[Experimental example]

Experimental Example 1

A TEM image of the conductive layer region without protrusions of the conductive particles according to Example 1 is shown in FIG. 2. According to this, the second palladium region, where palladium is distributed in the middle region of the conductive layer without protrusions, is confirmed to be purple.

In addition, Figure 3 shows the results of EDAX analysis of the middle region of the protrusion-free region of the conductive layer. It is confirmed that Ni is distributed throughout the conductive layer, but there is a second palladium region in the middle region.

Experimental Example 2

A TEM photograph of the protruding area of the conductive layer of the conductive particles according to Example 1 is shown in FIG. 4. According to this, the third palladium region, where palladium is distributed in the middle region of the conductive layer, is confirmed to be purple.

In addition, Figure 5 shows the results of EDAX analysis in the middle region of the protrusion, confirming that there is a third palladium region in which palladium nanoclusters are distributed in the center of the protrusion.

A TEM-EDAX analysis photo of the conductive particle according to Example 1 is shown in FIG. 2, and according to this, it was confirmed that there was no Pd or a very small amount of Pd in the area where there were no protrusions of the conductive layer.

The features, structures, effects, etc. illustrated in each of the above-described embodiments can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

10: First palladium area
20: Second palladium area
30: Third Palayoum area

Claims (12)

A conductive particle comprising a core and a conductive layer provided on the surface of the core and including protrusions,
The conductive layer containing the protrusions is,
A first palladium region where palladium nanoparticles are formed and distributed at the interface with the core;
A second palladium region where palladium nanoparticles are formed and distributed inside the middle of the conductive layer, and
It includes a third palladium region in which palladium nanoparticles are formed in the inner region of the protrusion and distributed as palladium nanoclusters,
The conductive layer including the protrusions is a conductive particle made of a single layer of polycrystalline based on nickel. delete According to paragraph 1,
Conductive particles containing palladium nanoclusters with an average particle diameter of 30 nm to 130 nm in the third palladium region. According to paragraph 1,
The first palladium region is a conductive particle in which more palladium nanoparticles are distributed than the surrounding area, and the palladium nanoparticles are attached to more than 95% of the core surface area. According to paragraph 1,
The second palladium region is a conductive particle in which more palladium nanoparticles are distributed than the surrounding area. According to paragraph 1,
A conductive particle in which the palladium concentration in the third palladium region is higher than the palladium concentration in the first palladium region or the second palladium region. According to clause 6,
The conductive layer is a conductive particle made of one or two or more alloys selected from the group consisting of Ni, Sn, Ag, Cu, Pd, Zn, W, P, B, and Au. In clause 7,
A conductive particle further comprising an insulating layer or insulating particles on the surface of the conductive layer. According to clause 8,
Conductive particles that have been treated to prevent rust on the outermost layer of the conductive layer using a hydrophobic rust preventive agent. An anisotropic conductive material containing the conductive particles of any one of claims 1 and 3 to 9. A connection structure comprising the conductive particle of any one of claims 1 and 3 to 9. A method for producing conductive particles having a conductive layer containing protrusions, comprising:
A) manufacturing the core;
B) attaching palladium particles to the surface of the core;
C) dispersing the core after step B) in a nickel plating solution;
D) injecting a nickel precursor after step C);
E) adding a reducing agent after step D) and then injecting a palladium precursor solution;
F) forming palladium nanoclusters by adding a palladium precursor solution, a reducing agent, and a stabilizer after step E); and
G) Including the step of injecting a nickel precursor after step F),
The conductive layer containing the protrusions is
A first palladium region where palladium nanoparticles are formed and distributed at the interface with the core;
A second palladium region where palladium nanoparticles are formed and distributed inside the middle of the conductive layer, and
A method for producing conductive particles comprising a third palladium region in which palladium nanoparticles are formed in the inner region of the protrusions and distributed as palladium nanoclusters, and the conductive layer containing the protrusions is made of a single layer of polycrystalline based on nickel. .